Optical edge touch sensor

ABSTRACT

An optically transmissive element of a computing device can be used to enable touch input. One or more light sources, such as infrared (IR) light emitting diodes (LEDs), can direct radiation into an edge or side of the transmissive element and direct light to reflect from at least one other side or edge using total internal reflection (TIR). If a user places a finger at a position where the light reflects from an edge of the element, a portion of the light will be transmitted out of the element causing a reduction in the amount of light received to one or more light sensors. By monitoring losses for one or more light sources across one or more light sensors, locations at which losses occur can be determined. These locations can correspond to various types of user input.

BACKGROUND

As people are increasingly using portable computing devices for a widervariety of purposes, it can be advantageous to adapt the ways in whichpeople interact with these devices. While various types of touch-freeinput are being used for a variety of purposes, there are still varioustypes of inputs that many people like to provide using a physicalcontact approach. For example, a user holding a cell phone to thatuser's ear might like to adjust a volume during a call by pressingvolume buttons or spinning a volume wheel. Similarly, a user holding apersonal data assistant might want to select a line of text using a sideof the device, without having to use the user's other hand to manuallyselect that line through a touch screen or similar input. Due to thenumber of types of possible input, it can be prohibitively expensiveand/or complex to attempt to place enough physical dials or buttonsaround a periphery of the device to provide the desired functionality.Further, an over abundance of input mechanisms can make the device seemdifficult to operate, or at least can make the device less visuallyappealing, which can negatively impact sales.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments in accordance with the present disclosure will bedescribed with reference to the drawings, in which:

FIGS. 1( a) and 1(b) illustrates an example situation wherein a user isinteracting with a computing device that includes a plurality of lightemitting elements operable to generate light that is coupled out of adisplay screen to provide a pattern to be displayed on the device inaccordance with various embodiments;

FIG. 2 illustrates an example of a light bar including a plurality oflight emitting diodes LEDs positioned to direct light into a displayelement that can be used in accordance with various embodiments;

FIG. 3 illustrates a first configuration of light emitters and detectorsfor a display element that can be used in accordance with variousembodiments;

FIGS. 4( a) and 4(b) illustrate example intensity patterns that can beanalyzed in accordance with various embodiments;

FIG. 5 illustrates a second configuration of light emitters anddetectors for a display element that can be used in accordance withvarious embodiments;

FIG. 6 illustrates a third configuration of light emitters and detectorsfor a display element that can be used in accordance with variousembodiments;

FIGS. 7( a) and 7(b) illustrate example computing devices that can beutilized in accordance with various embodiments;

FIG. 8 illustrates an example process for determining one or more usertouch locations that can be utilized in accordance with variousembodiments;

FIG. 9 illustrates an example set of components that can be utilized ina device such as that illustrated in FIG. 7( a) or 7(b); and

FIG. 10 illustrates an example an environment in which variousembodiments can be implemented.

DETAILED DESCRIPTION

Systems and methods in accordance with various embodiments of thepresent disclosure may overcome one or more of the aforementioned andother deficiencies experienced in conventional approaches to providinginput to, or determining information for, an electronic device. Inparticular, approaches discussed herein enable an electronic device toutilize an existing display element or other optically transparentcomponent to determine one or more locations where the user is touchingan edge or side of the element, in order to provide input to the device.In at least some embodiments, the device can also detect changes inpressure applied to the side of the element through changes in thedetected contact area of the user's finger(s) with respect to the edgeof the element.

In various embodiments, a set of light sources and a set of lightsensors are positioned such that the light sources are each able to emitlight into an edge of a layer of a display element and the light sensorsare each able to detect at least a portion of that light when emittedfrom the same, or another, edge of that layer. It should be understoodthat in various embodiments the layer does not need to be part of adisplay element, and that in certain embodiments the layer may comprisethe display element itself. The layer in at least some embodimentscomprises a medium formed of an optically transmissive material, such asglass or a clear polymer, with substantially few optical defects orcontaminants that could otherwise affect the transmission of radiationwithin the medium.

The light sources (which in some embodiments could comprise a singlephysical source with the light split into multiple beams or other suchconfigurations) can be positioned and/or configured such that the lightfrom each light source internally reflects off of at least one surfaceof the transmissive medium. The angle at which the light is incident on,and reflected from, the edge can be selected such that the lightundergoes “total” internal reflection (TIR), whereby at least a majorityof the light is reflected back into the medium with only a small amountof light being emitted from that edge due primarily to imperfections inthe medium, contaminants on the edge, or other such issues. The lightreflected back from the edge can then be detected by at least one lightsensor. In some embodiments, the light might reflect off more than oneedge before being incident on a sensor, or might be at least partiallyincident on multiple sensors along multiple edges of the medium.

Due to the difference in refractive indices between ambient air and themoisture, oils, and other materials present upon a user pressing afinger on the transmissive material, the amount of light reflected andtransmitted by an edge can change based on the presence of a finger orsimilar object at the edge position at which a light path is incident.By monitoring changes in the intensity of light received to at least onerespective light sensor, a computing device can determine whether (andwhen) a user contacted the edge at a given location. By using an arrayof light paths covering at least a substantial portion of at least oneedge of the transmissive medium, the computing device can monitorvarious user interactions with the edge(s) and determine various typesof user input to the device in response to those interactions.

Many other alternatives and variations are described and suggested belowin relation to at least some of the various embodiments.

FIG. 1 illustrates an example situation 100 wherein a user 102 isinteracting with a portable computing device 104. The computing device104 can be any appropriate device, such as a smart phone, tabletcomputer, or personal data assistant. In this example, the user 102 isholding the device in the user's right hand. In many cases, the user caninteract with one or more buttons on the side of the device, anddepending on the size of the device can reach a portion of the keys onthe front of the device or graphical elements displayed on a displayscreen 106. As mentioned, the number of buttons or physical inputelements that can be placed on a side of the device can be limited dueat least in part to space, visual appearance, or other such aspects.Further, if the user 102 uses the display element 106 to make selectionsthe user must block at least a part of the display to provide input, anddepending upon aspects such as the size and form factor of the devicemight have to use two hands to provide the desired input, which might beless than desirable for some users in at least certain situations.

FIG. 1( b) shows an example of a computing device 120 that enables auser to enter information through contact with the front surface of adisplay element 122. As known in the art, a multi-layer display elementcan provide for pressure-based input through resistive or capacitivetouch-based approaches. A resistive touch-based element typicallydetects a touch location by the contact location of two layers of aresistive material of the display element. A capacitive touch-basedapproach detects a touch location by determining the change in theelectrostatic field of a display element in response to the touch of anelectrical conductor, such as a human finger. The touch functionality istypically provide via layers that are distinct from the actual displaylayer, which can include a clear material having light from a light bar124 coupled into it as known in the art.

While such elements could be used on the sides of a device such as thatillustrated in FIG. 1( a), there can be various potential disadvantagesto such an approach. For example, a resistive approach might require useof a material on the edge of the device that is at least partiallysusceptible to damage, similar to the display on a device. Oftentimes,users want the sides and back of the device to provide a relativelydurable casing to prevent damage to the device upon dropping the deviceor another such occurrence, such that users might not want resistivetouch layers on the sides of the device. Similarly, capacitivemechanisms may also be less durable, and may be affected by changes intemperature or other such variations.

It therefore can be desirable to provide a way for users to interactwith one or more sides of the device to provide input, withoutsignificantly affecting the durability of the device or providing anumber of different physical mechanisms that can be visuallyunappealing, potentially inconvenient to operate, and can potentiallyprevent use of protective casings or other such elements. It further canbe desirable to utilize existing components and/or technology to theextent possible, in order to conserve volume in the device, lowerproduction costs, and prevent unnecessarily complicating the device.

FIG. 2 illustrates an example configuration 200 of a light bar 204 anddisplay element that can be used in accordance with various embodiments.As used herein, “light bar” can refer generically to any array orassembly of illumination elements that may or may not be connected toeach other by a physical bar or other such assembly, but may simply bemounted on a printed circuit board (PCB) or flexible substrate, etc. Inthis example, the display element 202 is shown in a “top view” and theradiation 212 propagating through the display element is light (e.g.,visible or infrared (IR)) from the light sources (e.g., LEDs) of thelight bar. In conventional displays the light from the LEDs might bedirected through a grating layer before being directed up and out of thedisplay, which would be out of the plane of FIG. 2. It should beunderstood, however, that orientations and directions such as “up” and“front” when referring to a device are used for purposes of simplicityof explanation, and are not intended to require a certain orientationunless otherwise stated. In various embodiments, however, a light barused for touch input might be positioned or configured such that thelight is incident directly into a side of the transmissive material 202.In some embodiments, the same light bar might be used for the touchinput as is used for the display, with one or more optical elementsbeing used to direct light from one or more of the LEDs into a side ofthe transmissive element instead of into a grating or other component ofthe display.

The light bar 204 in this example includes a set of infrared LEDs 206,which can produce radiation that is undetectable to the human eye andcan enable touch input to be provided without affecting the visibleappearance of an image displayed on respective a computing devicescreen, or distracting the user with radiation emitted from one or moresides of the display. These LEDs can be driven by control circuitry 210to direct light along determined paths in the transmissive medium, withthe light from the various sources capable of being generatedconcurrently, one at a time, or in various other combinations asdiscussed or suggested elsewhere herein. In cases were a laser diode orsimilar element is used as discussed later herein, the same or separatecircuitry can be used to separately drive the laser diode, as well asthe light sources for image display, backlighting, and other suchpurposes. In some embodiments, the light bar 204 might include a set ofIR LEDs placed between each adjacent pair of visible light LEDs used forimage display.

In some embodiments, it can be desirable to separate the IR LEDs fromthe other LEDs, for any of a number of purposes such as space or heatconcerns. In embodiments where multiple light bars are used, theseparation of LEDs on different light bars further enables the differentgroups of LEDs to be controlled and activated separately, which can helpto conserve power and reduce heat. For example, a right handed usermight prefer to provide input on a different side of the device from aleft handed holder, and applications such as games might require verydifferent input than Web browsing or other such activities.

FIG. 3 illustrates an example of a touch input configuration 300 thatcan be used in accordance with various embodiments to determine inputfor a single side of a computing device. It should be understood thatsuch an approach could be used with any appropriate side or edge of thetransmission medium, and that multiple such configurations can be usedwith the same medium in accordance with the various embodiments.

In this example, a set of light sources 304, 306, 308, 310 (e.g., LEDs)is positioned such that light emitted by the light sources is incidenton a determined side or edge 328 of a transmissive medium 302, such as aglass or plastic layer of a display element. Although four light sourcesare shown, it should be understood that there can be any appropriatenumber of light sources selected based upon factors such as the size ofthe device, the desired amount of sensitivity, the amount of powerrequired, the angular spread of the light emitted, and other suchfactors. Further, although the light from each source is shown as acollimated beam in this example, it should be understood that the beamsshown correspond to a primary path direction for each light source, andthat there can be varying amounts of beam spread among the variousembodiments. In some embodiments, the beams might at least partiallyoverlap each other during at least a portion of the path lengths. Insome embodiments, lasers or other beam-emitting elements can be usedthat might generate a beam pattern such as the one that is displayed inFIG. 3.

In the configuration 300 of FIG. 3, the light sources 304, 306, 308, 310are arranged such that light from each source is primarily incidentalong a determined portion 320, 322, 324, 326 of an edge 328 of thetransmissive medium. The incident angles are selected such that, for aninterface with ambient air or a similar environment, a substantialamount of the light from each light source undergoes TIR and is directedback into the transmissive medium at a corresponding angle ofreflection. The reflected light is directed to be incident on at leastone of a set of light sensors 312, 314, 316, 318 or other such elements(e.g., radiation detectors, IR sensors, or photodiodes). For example,the light from light source 304 is incident primarily in region 320,then reflected so as to be detected primarily by sensor 318. As shouldbe apparent, some light from each source might be detected by othersensors as well due to factors such as beam spread, imperfections in thetransmissive medium 302, and the like. In the case of imperfections inthe medium or other aspects inherent to the particular elements, acalibration procedure can be used that takes into account the variationsin intensity due to these elements. For example, if less light from onesource is receive than from the other sources due to a bubble or crackin the transmissive element, for example, this different can bedetermined through a calibration procedure and used as a baseline orsimilar set of values from which variations will be measured.

As mentioned, the amount of light reflected internally from the edge ofthe medium is due at least in part to the difference in the indices ofrefraction between the transmissive medium 302 and the environment onthe other side of the edge, which typically will be ambient air. Certainchanges in that index can change the critical angle at which the lighttotally internally reflects, and can cause at least a portion of thelight from that area to be transmitted through the edge instead of beingreflected. For example, if a user places a finger within region 324, theoils, moisture, and other aspects of the user's finger can change theratio of the refractive indices and the critical angle, reducing theamount of light reflected by the edge and ultimately received by atleast one sensor 314. By knowing where along the edge 328 the light wasreflected (region 324) the device (or a system or service incommunication with the device) can determine where along the edge theuser touched with a finger, within a given range of certainty. As thelight can be most intense along a center portion of that region,variations in intensity reduction can occur due to factors such as thedistance from the center point where the user touched and the size ofthe finger or region which is contacted. As discussed elsewhere herein,the amount of pressure applied by the finger can also affect the amountof light reflected, as placing more pressure with a finger along theedge will cause the contacting surface of the finger with respect to thetransmissive medium to “spread out” and contact more of the edge, whichcan further decrease the amount of light reflected and ultimatelyreceived by the corresponding sensor.

FIGS. 4( a) and 4(b) illustrate an example of how the measured intensitycan be used to determine a place of input along an edge in accordancewith various embodiments. In the plot 400 of FIG. 4( a), there areintensity curves 402 for each of four sensors. As discussed, each sensorcan measure light reflected by an edge for a corresponding primary lightsource, with some amount of overlap in this example to provide forcontinuity in input location. The intensity information for each sensorhas been calibrated and the results normalized such that when no fingeror other such object is touching the edge, a relatively consistentintensity curve 404 is obtained by aggregating the measured intensityover distance, which also can be normalized to run from 0 to 1. Thedistance can be an edge distance or a distance across the array ofsensors, which then can be correlated with an edge distance. It shouldbe understood that the values do not need to be normalized in allembodiments, and various sensor selections and configurations can beused within the scope of the various embodiments.

FIG. 4( b) illustrates an example plot 420 illustrating a change in theoverall intensity curve 424 in response to a user touching an area on anedge of the transmission medium from which the light is reflecting. Inthis example, the user has touched the edge in a location that isprimarily located with light received by one of the sensors, resultingin a reduction in the intensity of light received by that sensor, asillustrated by the change in shape of the individual intensity curve 422measured by that sensor. It should be understood that for overlappingsensor measurements and/or light reflection regions a finger locationmight cause a reduction in the measured intensity of two or moreintensity curves. In at least some embodiments, the relative reductionin the intensity of two adjacent intensity curves can be used tointerpolate the approximate position of the finger with respect to thetwo reflection regions associated with those sensors.

In at least some embodiments, the overall intensity curve 424 can beanalyzed to determine one or more locations 426 where the intensitydecreased, and by how much. This information can be used to determinewhere the edge was touched (based at least in part upon the path of thelight associated with that position) and the amount of the edge that wascontacted (as may be based at least in part upon the amount of reductionin intensity). In some embodiments, particularly where there are a largenumber of sensors or sensor elements, a relative intensity valuemeasured by each element could be compared which can provide a moresimple processing approach for a more complex physical system. Variousother approaches can be used as well as should be apparent to one ofordinary skill in the art in light of the present disclosure.

As discussed, an approach such as that illustrated in FIG. 3 can beduplicated for at least one additional edge in order to provide touchinput determinations on multiple edges. In at least some cases, however,this may require additional sensors and/or light sources, or at leastadditional elements operable to selectively direct light to differentedges of the transmissive medium.

FIG. 5 illustrates an alternative configuration 500 that can be used inaccordance with various embodiments. In this example there is still asingle set of light sources 504, 506, 508, 510 and a single set of lightsensors 528, 530, 532, 534, as in the example of FIG. 3. In this case,however, the light from each of the light sources is configured suchthat the light reflects from multiple edges, sides, or other surfaces ofthe transmissive medium 502 before being received by at least one of thelight sensors. For example, the light from a first source 504 reflectsfrom a first region 512 on a first edge 536 of the medium then isreflected again (from two edges in this example) to a second region 520on another edge 538, before being reflected to a first light sensor 528.In some embodiments where the user can provide the same input downeither side 536, 538 based on the corresponding lateral position, theordering of the reflection region 512, 514, 516, 518 for one side cancorrespond to the same ordering of light paths as the ordering 520, 522,524, 526 on the opposite side. In this way, a reduction in intensitydetected by any of the sensors provides an appropriate input, regardlessof the side which the user touched. For example, the beam from source506 reflects from regions 514 and 522, which correspond to the sameapproximate lateral position along the opposite edges of thetransmission medium 502. A user thus can provide the same input usingeither side of the medium. In some embodiments, a user can provide“squeeze” or dual side input by pressing at the same lateral location oneach side of the transmission medium 502. For example, the user couldconcurrently press on regions 518 and 526. The intensity measured bysensor 534 would then drop by more than if the user touched eitherregion individually, as both regions would transmit some light due tothe presence of a finger. Such an approach thus can provide anadditional input by detecting where multiple fingers are touching.

In some embodiments, however, the light paths can be configured toreflect from different edges in different locations and/or orders. Forexample, a pair of light sources might be oriented such that the pairreflects from a first edge in a first order, such as the light from thefirst source being incident on the first edge before the light from thesecond source, but switched on a subsequent bounce, such that the lightfrom the second source is incident on a second edge before light fromthe first source. Various patterns can be utilized to provide suchchanges in ordering as should be apparent to one of ordinary skill inthe art in light of the teachings and suggestions contained herein. Ifthere are enough light paths used that have different orderings ondifferent sides, then the edge which the user touches can be determinedby analyzing the relative drops in intensity of the different lightpaths. For example, if there are overlapping light paths from lightsources 1, 2, and 3 in order 1-2-3 incident on a first edge, and order1-3-2 incident on a second edge, the relative position and/or orderingscan be used to determine which edge and location was contacted. If thereis a drop in the light received from sources 1 and 3, for example, andthe spread corresponds to a single finger, then it can be determinedthat the finger was at a location on the second edge where the lightfrom sources 1 and 3 overlaps. Various other such approaches can be usedas well within the scope of the various embodiments.

In at least some embodiments where space is not as critical or the costis not prohibitive, other approaches can be used that utilize additionallight sources and/or light detectors. For example, FIG. 6 illustrates anexample configuration 600 wherein the location on opposing sides 646,648 on which a user touches can be determined using a single set oflight sources 604, 606, 608, 610. In this example, however, the patternis more simple due at least in part to the fact that a first set ofsensors 620, 622, 624, 626 is used to measure intensity of lightreflected from regions 612, 614, 616, 618 on a first edge 646 of thetransmissive material 602, and a second set of sensors 636, 638, 640,642 measures intensity of the light reflected from regions 628, 630,632, 634 on the second edge 648. In at least some embodiments, the lightincident on the edge 644 near the first set of sensors might not hit atan angle to cause total internal reflection. The edge 644 might have oneor more optical elements or layers, such as one or more beam splittersor partially reflective mirror layers, contained within or attached tothe edge such that a portion of the light from each source istransmitted by the edge 644, and a portion of the light is reflectedback into the transmissive medium 602. In this way, light from a singleset of sources 604, 606, 608, 610 can be used, which saves power versusmultiple sets, but the light reflected from each monitored edge 646, 648can be captured and analyzed using different sensors, enabling higheraccuracy and a simpler light pattern.

Such an approach can also be less processor intensive than otherapproaches. For example, if the user touches the transmissive medium 602at a first region 612 of a first side 646, the corresponding sensor 626will detect a drop in intensity which can provide a quick and easydetermination that the user contacted the edge at least partially withinthat region 612. If the user instead touched a similarly laterallylocated region 628 upon the opposing side 648, a corresponding drop inintensity would be detected by a different sensor 624. Such an approachthus can be more simple to implement and utilize in at least somesituations than other approaches discussed herein. Further, the shorterpath length needed to measure touch on opposing sides reduces losses andthe likelihood of defects being present in the beam paths, such thataccuracy can be further improved. As mentioned, however, such approachescan require more sensors or light sources, as well as more volume in thedevice, which may be undesirable in certain situations. As should beunderstood, various other light path patterns and combinations ofradiation sources and radiation detectors can be used within the scopeof the various embodiments.

In order to provide touch-based input using at least some of theapproaches discussed above, the user should be able to touch at least aportion of one or more edges of a transmissive medium on a device. Insome embodiments an entire edge might be positioned to be contacted by auser's finger, while in other embodiments enough of the edge must becontactable by a user's finger or other such object to cause at least adetectable change in intensity of light reflected from that edge. FIG.7( a) illustrates a first example of a computing device 700 where atransmissive layer 702 of a display element of the device is used toenable touch input. In this example, at least one edge 704 of thetransmissive layer is positioned near an edge of the device 700, such aswithin 2 mm of the edge of the device. Keeping the edge of the layerinset from the edge of the device can help to protect the transmissivelayer, which can be more susceptible to damage than the edge of thedevice itself. In this example, the edges of the transmissive layer arecovered by a portion of the casing that is deformable when a userpresses a finger or other object against that portion of the casing. Asdiscussed, the user can provide input by pressing on an appropriateregion of the deformable casing, which in turn will contact the edge andcause a decrease in the intensity of light reflected from that locationand detected by at least one corresponding sensor. Such an approachenables touch input while protecting the screen and preventing oil orother contaminants from collecting on the edge(s) of the transmissivelayer.

FIG. 7( b) illustrates another example computing device 750 enablingsuch input. In this example, however, the edge 754 of the transmissivematerial 752 monitored for touch input is flush with, or at leastsubstantially close to, the edge of the computing device 750. Such anembodiment enables an entire edge of the material to be contacted by auser's fingers in at least some embodiments, which can provide for agreater measurable decrease in the reflected intensity. As discussedabove, such designs also allow for input along at least two opposingsides of the devices, allowing for “squeeze” type input as discussedabove, as well as potentially side-independent input as may be importantfor left vs. right hand dominant users. Also as illustrated in thisfigure, a computing device can be configured to display one or moregraphical elements or other indicia on the display that is visiblethrough the optically transmissive material. In this example, thegraphical elements might be displayed when the device is in an activecall mode, where a first element 756 is displayed near a region of theedge where a user is to touch or press to increase a call volume, asecond element 758 is displayed near a region where the user is to touchor press to decrease a call volume, and a third element 760 is displayedto indicated to a user an area of the edge where the user can touch tohang up the call or perform a similar option. It should be understoodthat there can be any of a number of different elements displayed forany of a number of different functions, and that the selection candepend at least in part upon a current operational mode of the device,executing application, or other such aspect. In other embodiments,graphical icons might not be displayed, but visible light of one or morecolors might be directed to different regions of the edge to assist withdevice operation and/or input determination by the user. In someembodiments, a portion of the edge will be frosted, ground, or otherwiseprocessed to have a texture or roughness such that the light can be seenby a user when the light is incident upon that portion of the edge. Theedge can also include another portion that might be substantiallytransmissive in order to allow for intensity change determinations asdiscussed elsewhere herein. In some embodiments, at least a portion ofthe edge might be beveled or otherwise shaped such that the colors canalso be visible from a front or other direction with respect to thedevice.

FIG. 8 illustrates an example process 800 for determining touch input inaccordance with various embodiments. It should be understood, however,that there can be additional, fewer, or alternative steps performed insimilar or alternative orders, or in parallel, within the scope of thevarious embodiments unless otherwise stated. In this example, touch modeis activated 802 on a computing device. In some embodiments, touch modecan be active any time the device is active (and touch input is enabledby the user), upon the user manually activating touch mode, upon openingan appropriate application on the device, or upon any other such actionor event. In some embodiments, touch mode might be activated upondetecting motion near the device, the presence of a user near thedevice, upon detecting a user gesture, or upon detecting the userpicking up the device. Upon touch mode being activated, one or more LEDsor other such light sources can be activated 804 in order to provide thelight needed for touch detection. As discussed, this can involve one ormore light sources (and/or optical components) directing light into anat least partially transmissive material at an angle such that at leasta portion of the light will be reflected from at least one edge or sideof the transmissive material. The LEDs can be activated at anyappropriate time, such as upon detecting motion, for a period of timeafter a determined action or event, periodically, or continually, amongother times or approaches. The light reflected internally from one ormore edges of the material can be received 806 by one or more lightsensors, or at least portions, segments, or pixels of one or more lightsensors. As mentioned, there might be a set of sensors along a singleedge to monitor touches along one or more edges, or multiples sets ofsensors each positioned to measure light from a respective edgeposition, among other possible configurations. The light received toeach LED (or at least a relevant or respective portion of the LEDs) canbe compared 808 and or analyzed to determine a relative intensitybetween sensors, an overall intensity pattern, light losses, or othersuch intensity information. Using any of the approaches discussed orsuggested herein, the variations in received intensity among the varioussensors can then be used to determine 810 one or more locations along atleast one edge of the transmissive medium where the user contacted themedium with a finger or other such object. As discussed, various optionsexist that can enable multiple touch points or types of input to bedetected and processed in accordance with the various embodiments. Anappropriate input corresponding to the touch position(s) then can bedetermined 812, as may cause one or more appropriate actions to beperformed on the computing device.

In many embodiments discussed herein, the touch locations are determinedusing a “loss” in the amount of light received to one or more of thesensors due to the presence of a human finger along an edge of atransmissive medium causing some of the light to be transmitted from themedium and absorbed by the user's finger. In at least some embodiments,the sources of this light could be modulated such that the sensors arelooking for light at a particular pulsing frequency, such as pulsingfrequencies in the range of 10 kHz to 1 MHz. If the sensors are able tosufficiently lock into that pulsing frequency, other light can bedifferentiated and discarded or used for filtering. This other lightcould be, for example, ambient light incident on the transmissive mediumfrom the surrounding environment. In one embodiment, an LED is modulatedto 200 kHz, and the receiving circuit is tuned to that modulationfrequency as well in order to reject other light, such as may includeambient light or light from the display. In some embodiments, differentLEDs can be modulated at different frequencies, with the sensors and/orreceiving circuitry being modulated to corresponding frequencies suchthat light from different LEDs can be separated by modulation frequencyeven when those sources are received concurrently to the sensors, etc.

In some embodiments the LEDs can be pulsed for a very short burst at adetermined frequency, which can significantly reduce the amount of powerconsumed. For example, if the LEDs are pulsing at 100 kHz then thephotodiode reading circuitry might utilize a filter that only enablespulses at 100 kHz to pass. In addition to electronic filtering, someoptical filtering may be employed, for example if IR LEDs are used thephotodiodes might utilize relatively small filters that pass IR lightbut block visible light as might enter from the ambient lighting or fromthe display backlight. In some embodiments, the photodiodes can be ACcoupled such that any DC component (i.e., resulting from the room lightor daylight) is ignored. Further, the photodiodes can be very low powercomponents such that use of low duty cycle modulation for the LEDs canhelp provide for a very low power device, in addition to the immunity toambient light.

As mentioned, any or all of the edges of a transmissive layer or sheet,for example, can be exposed for contact by a human finger or other suchobject. In at least some embodiments, however, a casing material such asa rubber or polymer material can be placed around the edges that can bedeformed due to pressure from a human finger. In some embodiments, thecasing material might directly contact the edge of the transmissivelayer, while in other embodiments a material of a selected refractiveindex can be positioned between the rubber and the edge to increase (orcontrol) the amount of light transmitted. Such an approach would enablelight to be coupled into, and absorbed by, the casing material withouthaving to expose an edge of the transmissive layer to potential damage.In at least some embodiments, one edge might have a metallized barrieror other reflective material that helps to reflect the light back intothe transmissive layer, such that the light does not have to be incidentat a relatively oblique angle near the critical angle for TIR. Theability to require only one or two edges to have reflection at suchoblique angles can simplify the pattern for the device.

In at least some embodiments, the angle of the transmitted light can beconfigured to be incident upon at least one edge of the transmissivematerial at almost exactly the critical angle whereby the lightundergoes total internal reflection. Such an approach enables the deviceto be very sensitive to contact or other changes in external atmosphere.Such an approach can be potentially problematic in some situations,however, as slight misalignments can cause the light to be more likelyto be unintentionally transmitted by the edge, and any collection oroil, dirt, or other contaminants on the surface can cause an appreciableamount of light to be lost via the interface, although periodiccalibration and/or adjustment can handle relatively slow variations inreflected intensity over time. In at least some embodiments, a touchdetection algorithm is not searching for an absolute intensity thresholdvalue but a relative threshold value indicating contact, such that thelong term averages or other adjustments can handle many issues withcontamination, oil accumulation, and the like.

As discussed, the light paths are illustrated in the figures ascollimated beams, but it should be understood that the light canactually fan out into broader spreads with propagation distance.Additional optical elements can be used where desired to attempt toadjust or control the amount of spread of the various light paths.Further, the amount of light sources and/or detectors used can vary withthe amount of spread as well, particularly the amount of spread withrespect to the size of each edge, path length, and other such factors.For example, in some embodiments four LEDs might be sufficient to coveran entire edge, with a significant amount of overlap. The number ofdetectors used can depend at least in part upon the sensitivity of themeasurements, as differences in adjacent intensity measurements can beused to interpolate touch position to the accuracy of the number ofdetectors, pixels, or segments of those detectors, etc. In most casesthe detectors or sensors will get some amount of overlap from multiplelight sources, which helps with interpolation and touch locationdetermination. The use of a multiplexing scheme as discussed hereinfurther provides accurate position and side information by examining thelosses of adjacent beams, etc.

Other factors can affect the number of light sources and/or detectors aswell. For example, different use cases might require different touchlocations and/or levels of sensitivity. If a user wants to provide inputusing one or more fingers detected in specific locations along a side,then a relatively small number of light sources and detectors might beappropriate. If a user wants to be able to scroll down a page, zoom animage, or adjust a volume with a swiping motion, then a relatively smallnumber of light sources and detectors might not provide enoughinformation and might result in a jumping or jerking motion that is notsmooth or continuous, such that a larger number of light sources (e.g.,8 or 16) might be appropriate and sufficient for adequate interpolationdeterminations. Complex interpolation schemes might be able to be usedwith a smaller number of light sources, but the delay and processingdemands might be too great for at least some situations.

As mentioned, the light sources can be discrete sources or part of asingle component. For example, a package to be added to a computingdevice might include multiple LED elements and pin photodiodes placed ona substrate such as a board or flex. Such a package then can be adheredto, or otherwise positioned with respect to, an edge of the transmissivematerial. In one embodiment, an optical layer of a display element is0.5 mm thick such that the board with the LED elements can also beapproximately 0.5 mm wide, with a thickness on the order of a flex andthe height of a die, where a die is about 100 microns thick. The packagecan be positioned along an entire edge, or at least a portion of abottom edge, of the transmissive medium, where utilizing the entire edgecan help to reduce potential alignment issues. There also can be varyingamount of interleaving of LEDs, photodiodes, and other such componentsin the various embodiments.

The timing of the various light sources can also be adjusted, varied,and/or controlled differently among various embodiments and/or forvarious use cases. For example, LEDs may not need to be flashed at thesame time but can be flashed in sequences of various orders. Flashing atthe same time might result in cross-talk or other such issues for atleast some embodiments, such that it can be preferable to flash eachlight source separately and examine the corresponding flash at eachphotodiode. Since the beams might spread to multiple photodiodes, suchan approach can help to better determine an amount of intensity decreasecorresponding to different regions of the light path, which can helpimprove interpolation when combining results from the variousphotodiodes. The flashing frequency can be very fast, such as on theorder of microseconds, such that there might be no noticeable delay onthe part of the user. The flashing frequency can be selected so as tonot interfere with other components on the device, such as a camera orradio frequency component.

In some embodiments, a computing device can detect when a device isbeing picked up and/or held using any appropriate component(s), such asan inertial sensor or accelerometer, electronic gyroscope, touchsensitive material, and the like. When the device determines it is beingheld, for example, the device can determine a baseline intensity patterncorresponding to a time when the user is not contacting an edge of thetransmissive material. When the user then contacts an appropriate edge,the difference in intensity can be determined relative to that baselineunder current conditions. Further input can be determined based upon theway in which the intensity pattern changes. For example, a user tappinga location will provide a very easy to distinguish change in theintensity pattern with distinct loss variations. A user might tap toperform an action such as to take a picture or select an item. A useralso might slide a finger along a portion of an edge to, for example,zoom in or out in an image viewing application, which can also provide adistinguishable change in the detected intensity pattern. Various othermotions, gestures, or actions can provide distinguishable intensitypattern changes as well.

In at least some embodiments the touch detection can further be used toat least partially identify or authenticate a user of the device. Forexample, a user might typically contact the edges of the device in acertain way, such as with a certain separation of finger touch positionsbased on the way the user holds the device and/or physical aspects ofthe user's fingers. Similarly, the size of a user's fingers can cause acertain range of intensity changes due at least in part to the amount ofedge area that can be contacted by that user's finger. By monitoring theway in which a user contacts the device, the device can provide a firstlevel of security as to whether the current user matches the expecteduser or at least an authorized user.

In some embodiments, a more accurate identity authentication mechanismcan be provided. One such approach takes advantage of the fact that theuser can be required to touch the sides of the transmissive materialwith at least one finger to provide certain types of input in at leastsome embodiments. Various conventional devices such as certainfingerprint scanners utilize TIR to determine fingerprint informationusing an oil pattern on glass. By building on these conventionalapproaches, fingerprint scanning can also be implemented in a touchdetermination capable device. In one example, a light source such as alaser can be used to direct light to at least one location on an edge ofthe device. A user can swipe, roll, or perform another such action withthe user's finger on an edge of the device, and a laser diode or othersuch component having light reflected from that region using TIR canpotentially be used to determine at least a portion of a fingerprintusing various diffraction effects. Various points can be determined inFourier transform space of the reflected and diffracted beam with thefeatures of the fingerprint forming a unique grating pattern on thefrustrated reflection, or using a similar approach, which then can becompared against stored fingerprint pattern information for a user.Methods of matching fingerprints using such information are known in theart and will not be discussed in detail herein. Such approaches could beused to identify a user, provide for a secure device unlock withoutpassword entry, etc. In some embodiments, the laser could be fired uponcertain verification procedures, at various points in the LED flashingsequence, etc. When analyzing fingerprints, a single bounceconfiguration might be advantageous where the emitted light is onlyreflected from a region where the user might place his or her finger,then is received by a sensor without reflecting from another surface. Insome embodiments, only a portion of an edge might be exposed that isused to detect the reflected laser light.

As mentioned, the pressure of a touch can be determined in addition tothe localization of that touch by quantifying the light lost. Further,multiple concurrent touches or touch motions can be determined for oneor more edges. Various approaches known for such optical purposes can beused to reduce noise and background signal and increase signal-to-noiseratio and sensitivity. For example, the LEDs can be modulated on andoff, with the readings at the off stage being averaged and thensubtracted from the on state readings.

In some embodiments a device design can be configure to radius the edgeof the device. Such an approach not only prevents sharp edges that theuser might contact, but also can make better use of the emitted light.In some embodiments the edge of the phone could be scalloped as well,having several small formations with small radii. Such an approach couldpotentially improve the quality of the light with every bounce, and canhelp to re-collimate the beams based at least in part upon the radius ofa respective feature and the amount of beam spread.

FIG. 9 illustrates a set of basic components of an example computingdevice 900 such as the devices described with respect to FIG. 1( b).While a portable smart device is depicted in many examples herein, thecomputing device could be any appropriate device able to receive andprocess input commands, such as a personal computer, laptop computer,television set top box, cellular phone, PDA, electronic book readingdevice, video game system, or portable media player, among others. Inthis example, the device includes at least one processor 902 forexecuting instructions that can be stored in a memory device or element904. As known in the art, the device can include many types of memory,data storage or non-transitory computer-readable storage media, such asa first data storage for program instructions for execution by aprocessor 902, a separate storage for images or data, a removable memoryfor sharing information with other devices, etc.

The device typically will include at least one type of display element906, such as a liquid crystal display (LCD), organic light-emittingdiode (OLED) display, a plasma display, or a digital light processing(DLP) display, as discussed herein. The display element can include atleast one transmissive layer, element, or component that is at leastpartially exposed to contact by a user. The transmissive element cellcan be selected such that the element does not absorb an appreciableamount of light or IR radiation, such that the element can enabletransmission of a displayed image as well as propagation of radiationused to provide touch input, which might be in a direction transverse tothat of the light for image display. As mentioned, the device caninclude one or more illumination elements 910, such as IR LEDs, laserdiodes, or other such components, positioned with respect to thetransmissive element of the display 906 such that at least a portion ofthe light or radiation transmitted into an edge of the transmissiveelement is incident upon at least one internal edge of the transmissivemedium so as to undergo total internal reflection at least when theinterface of that edge is with ambient air or another such environment.The generation and timing of the radiation emission from theillumination element(s) 910 can be controlled using various controlcircuitry including components known and configured for purposes such aspulsing LEDs. At least a portion of the internally light or radiationthen can be detected by one or more light or radiation sensing elements908, such as IR sensors or light detectors, photodiodes, and the like.In at least some embodiments, illumination elements 910 and lightsensing elements 908 are configured to handle IR radiation over anappropriate wavelength, such as 940 nm or other wavelengths above 900nm. The detectors can be any appropriate detectors, such as CMOS sensorsoperable to detect radiation in a wavelength range of at least, forexample, 910 nm to 970 nm. In embodiments using multiple IR LEDs, theLEDs can be scanned in sequence for some applications in order to reducepower consumption or simplify touch location determination. For otherapplications, various subsets of the IR LEDs can be used at differenttimes in order to illuminate various portions or regions, etc.

An example computing device also can include other components, such asat least one motion-determining element (e.g., an accelerometer or gyroelement) that can be used to determine motion of the device, which canbe used to trigger or adjust a touch input mode as discussed elsewhereherein. The device can also include at least one image capture elementfor capturing ambient light image information about the user of thedevice. The imaging element may include, for example, a camera, acharge-coupled device (CCD), a motion detection sensor, or a radiationsensor, among many other possibilities.

The device can support other types of input as well. For example, thedevice can include a touch- and/or pressure-sensitive element around atleast a portion of the device, such as on the back and/or sides of thedevice. Using such material, the device is able to determine whether auser is actively holding the device and/or can enable the user to applyinput by squeezing at least a portion of the device. The inputinformation could be used to trigger a detection mode or other suchprocess. The device can also include a microphone or other suchaudio-capturing device. The device in at least some embodiments cantrigger various actions or modes based upon sound detected by themicrophone. For example, if the device detects speech from a person, thedevice might activate a detection mode to enable that person to providemotion input. The device can include at least one additional inputdevice able to receive conventional input from a user. This conventionalinput can include, for example, a push button, touch pad,touch-sensitive element used with a display, wheel, joystick, keyboard,mouse, keypad or any other such device or element whereby a user caninput a command to the device.

In some embodiments, one or more icons or other notifications might bedisplayed on the device to indicate to the user that IR illumination isactive, or that touch determination is being performed. In someembodiments, a light (e.g., LED) on the device might illuminate in orderto notify the user that touch detection is activated in order to signalto the user that the user can provide input via various motions orfinger positions. Various other notifications can be used as well asappropriate.

A computing device used for such purposes can operate in any appropriateenvironment for any appropriate purpose known in the art or subsequentlydeveloped. Further, various approaches discussed herein can beimplemented in various environments for various applications or uses.Portions of the analysis also can be sent or offloaded to remote deviceswhich might have more available resources and/or capacity. For example,FIG. 10 illustrates an example of an environment 1000 for implementingaspects in accordance with various embodiments. As will be appreciated,although a Web-based environment is used for purposes of explanation,different environments may be used, as appropriate, to implement variousembodiments. The environment 1000 shown includes a variety of electronicclient devices 1002, which can include any appropriate device operableto send and receive requests, messages, or information over anappropriate network 1004 and convey information back to a user of thedevice. Examples of such client devices include personal computers, cellphones, handheld messaging devices, laptop computers, set-top boxes,personal data assistants, electronic book readers, and the like. Eachclient device can be capable of running at least one motion ororientation-controlled interface as discussed or suggested herein. Insome cases, all the functionality for the interface will be generated onthe device. In other embodiments, at least some of the functionality orcontent will be generated in response to instructions or informationreceived from over at least one network 1004.

The network 1004 can include any appropriate network, including anintranet, the Internet, a cellular network, a local area network, or anyother such network or combination thereof. Components used for such asystem can depend at least in part upon the type of network and/orenvironment selected. Protocols and components for communicating viasuch a network are well known and will not be discussed herein indetail. Communication over the network can be enabled by wired orwireless connections, and combinations thereof. In this example, thenetwork includes the Internet, as the environment includes a primarycontent provider 1006 and a supplemental content provider 1008. Eachprovider can include at least one Web server 1006 for receiving requestsfrom a user device 1002 and serving content in response thereto,although for other networks an alternative device serving a similarpurpose could be used as would be apparent to one of ordinary skill inthe art.

Each content provider in this illustrative environment includes at leastone application server 1012, 1014, 1022 or other such server incommunication with at least one data store 1016, 1018, 1024. It shouldbe understood that there can be several application servers, layers,and/or other elements, processes, or components, which may be chained orotherwise configured, which can interact to perform tasks such asobtaining data from an appropriate data store. As used herein the term“data store” refers to any device or combination of devices capable ofstoring, accessing, and retrieving data, which may include anycombination and number of data servers, databases, data storage devices,and data storage media, in any standard, distributed, or clusteredenvironment. An application server can include any appropriate hardwareand software for integrating with the data store as needed to executeaspects of one or more applications for the client device, handling amajority of the data access and business logic for an application. Theapplication server provides access control services in cooperation withthe data store, and is able to generate content such as text, graphics,audio, and/or video to be transferred to the user, which may be servedto the user by the Web server in the form of HTML, XML, or anotherappropriate structured language in this example. The handling of allrequests and responses, as well as the delivery of content between theclient device 1002 and an application server, can be handled by therespective Web server. It should be understood that the Web andapplication servers are not required and are merely example components,as structured code discussed herein can be executed on any appropriatedevice or host machine as discussed elsewhere herein. Further, theenvironment can be architected in such a way that a test automationframework can be provided as a service to which a user or applicationcan subscribe. A test automation framework can be provided as animplementation of any of the various testing patterns discussed herein,although various other implementations can be used as well, as discussedor suggested herein.

Each data store can include several separate data tables, databases, orother data storage mechanisms and media for storing data relating to aparticular aspect. For example, the page data store 1016 illustratedincludes mechanisms for storing page data useful for generating Webpages and the user information data store 1018 includes informationuseful for selecting and/or customizing the Web pages for the user. Itshould be understood that there can be many other aspects that may needto be stored in a data store, such as access right information, whichcan be stored in any of the above listed mechanisms as appropriate or inadditional mechanisms in the data store. Each data store is operable,through logic associated therewith, to receive instructions from arespective application server and obtain, update, or otherwise processdata in response thereto. In one example, a user might submit a searchrequest for a certain type of content. In this case, the data storemight access the user information to verify the identity of the user,and can access the content information to obtain information aboutinstances of that type of content. The information then can be returnedto the user, such as in a results listing on a Web page that the user isable to view via a browser on the user device 1002. Information for aparticular instance of content can be viewed in a dedicated page orwindow of the browser.

Each server typically will include an operating system that providesexecutable program instructions for the general administration andoperation of that server, and typically will include a computer-readablemedium storing instructions that, when executed by a processor of theserver, allow the server to perform its intended functions. Suitableimplementations for the operating system and general functionality ofthe servers are known or commercially available, and are readilyimplemented by persons having ordinary skill in the art, particularly inlight of the disclosure herein.

The environment in one embodiment is a distributed computing environmentutilizing several computer systems and components that areinterconnected via communication links, using one or more computernetworks or direct connections. However, it will be appreciated by thoseof ordinary skill in the art that such a system could operate equallywell in a system having fewer or a greater number of components than areillustrated in FIG. 10. Thus, the depiction of the system 1000 in FIG.10 should be taken as being illustrative in nature, and not limiting tothe scope of the disclosure.

Various embodiments discussed or suggested herein can be implemented ina wide variety of operating environments, which in some cases caninclude one or more user computers, computing devices, or processingdevices which can be used to operate any of a number of applications.User or client devices can include any of a number of general purposepersonal computers, such as desktop or laptop computers running astandard operating system, as well as cellular, wireless, and handhelddevices running mobile software and capable of supporting a number ofnetworking and messaging protocols. Such a system also can include anumber of workstations running any of a variety ofcommercially-available operating systems and other known applicationsfor purposes such as development and database management. These devicesalso can include other electronic devices, such as dummy terminals,thin-clients, gaming systems, and other devices capable of communicatingvia a network.

Most embodiments utilize at least one network that would be familiar tothose skilled in the art for supporting communications using any of avariety of commercially-available protocols, such as TCP/IP, OSI, FTP,UPnP, NFS, CIFS, and AppleTalk. The network can be, for example, a localarea network, a wide-area network, a virtual private network, theInternet, an intranet, an extranet, a public switched telephone network,an infrared network, a wireless network, and any combination thereof.

In embodiments utilizing a Web server, the Web server can run any of avariety of server or mid-tier applications, including HTTP servers, FTPservers, CGI servers, data servers, Java servers, and businessapplication servers. The server(s) also may be capable of executingprograms or scripts in response requests from user devices, such as byexecuting one or more Web applications that may be implemented as one ormore scripts or programs written in any programming language, such asJava®, C, C# or C++, or any scripting language, such as Perl, Python, orTCL, as well as combinations thereof. The server(s) may also includedatabase servers, including without limitation those commerciallyavailable from Oracle®, Microsoft®, Sybase®, and IBM®.

The environment can include a variety of data stores and other memoryand storage media as discussed above. These can reside in a variety oflocations, such as on a storage medium local to (and/or resident in) oneor more of the computers or remote from any or all of the computersacross the network. In a particular set of embodiments, the informationmay reside in a storage-area network (“SAN”) familiar to those skilledin the art. Similarly, any necessary files for performing the functionsattributed to the computers, servers, or other network devices may bestored locally and/or remotely, as appropriate. Where a system includescomputerized devices, each such device can include hardware elementsthat may be electrically coupled via a bus, the elements including, forexample, at least one central processing unit (CPU), at least one inputdevice (e.g., a mouse, keyboard, controller, touch screen, or keypad),and at least one output device (e.g., a display device, printer, orspeaker). Such a system may also include one or more storage devices,such as disk drives, optical storage devices, and solid-state storagedevices such as random access memory (“RAM”) or read-only memory(“ROM”), as well as removable media devices, memory cards, flash cards,etc.

Such devices also can include a computer-readable storage media reader,a communications device (e.g., a modem, a network card (wireless orwired), an infrared communication device, etc.), and working memory asdescribed above. The computer-readable storage media reader can beconnected with, or configured to receive, a computer-readable storagemedium, representing remote, local, fixed, and/or removable storagedevices as well as storage media for temporarily and/or more permanentlycontaining, storing, transmitting, and retrieving computer-readableinformation. The system and various devices also typically will includea number of software applications, modules, services, or other elementslocated within at least one working memory device, including anoperating system and application programs, such as a client applicationor Web browser. It should be appreciated that alternate embodiments mayhave numerous variations from that described above. For example,customized hardware might also be used and/or particular elements mightbe implemented in hardware, software (including portable software, suchas applets), or both. Further, connection to other computing devicessuch as network input/output devices may be employed.

Storage media and computer readable media for containing code, orportions of code, can include any appropriate media known or used in theart, including storage media and communication media, such as but notlimited to volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information such as computer readable instructions, data structures,program modules, or other data, including RAM, ROM, EEPROM, flash memoryor other memory technology, CD-ROM, digital versatile disk (DVD) orother optical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other medium which canbe used to store the desired information and which can be accessed by asystem device. Based on the disclosure and teachings provided herein, aperson of ordinary skill in the art will appreciate other ways and/ormethods to implement the various embodiments.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that various modifications and changes may be made thereuntowithout departing from the broader spirit and scope of the invention asset forth in the claims.

What is claimed is:
 1. A computing device, comprising: a liquid crystaldisplay (LCD) element including an optically transmissive layer havingat least one side surface being substantially orthogonal with respect toan exposed front surface of the LCD, the side surface at least partiallyexposed, the side surface further being configured to receive a userinput corresponding to a finger of the user contacting the side surface;an infrared (IR) light emitting diode (LED) positioned to direct IRradiation into the optically transmissive layer such that at least aportion of the IR radiation from the LED incident on an internal surfaceof the at least one at least partially exposed side surface of theoptically transmissive layer undergoes total internal reflection (TIR)when the at least one at least partially exposed side surface is not incontact with a finger of a user; at least one IR detector operable todetect IR radiation reflected by the internal surface of the at leastone at least partially exposed side surface and transmitted through atleast one side surface of the optically transmissive layer; and aprocessor configured to execute instructions to analyze the detected IRradiation to determine variations in a measured intensity of the IRradiation, the processor further operable to determine a reflectionposition corresponding to a decrease in the measured intensity, thedecrease in the measured intensity at the reflection position beingindicative of the finger of the user contacting the at least one atleast partially exposed side surface at the reflection position when thedecrease in the measured intensity with respect to a default measuredintensity at least meets a threshold value.
 2. The computing device ofclaim 1, further comprising: a control circuitry in electroniccommunication with the processor and operable to selectively activatethe IR LED in response to a control signal from the processor.
 3. Thecomputing device of claim 2, wherein the IR LED is one of a plurality ofIR LEDs, and wherein the control circuitry is programmed to activate theplurality of IR LEDs individually in sequence whereby the at least oneIR detector is capable of distinguishing light from each of theplurality of IR LEDs.
 4. The computing device of claim 3, wherein theprocessor is operable to perform interpolation on intensity measurementsfor the plurality of IR LEDs to determine at least one position of anobject in contact with the at least one at least partially exposed sidesurface of the optically transmissive layer causing a reduction in themeasured intensity.
 5. The computing device of claim 1, wherein the atleast one IR detector comprise a first set of IR sensors operable todetect a first portion of the IR radiation reflected from a firstinternal surface and a second set of IR sensors operable to detect asecond portion of the IR radiation reflected from a second internalsurface.
 6. The computing device of claim 1, wherein multiple IRradiations from the IR light emitting diode are directed into theoptically transmissive layer, and wherein beams of IR radiation from theIR light emitting diode are incident on a first internal surface in adifferent order than the beams are incident on a second internalsurface.
 7. A computing device comprising: a processor; a liquid crystaldisplay (LCD) element including an optically transmissive element havingat least one side surface being substantially orthogonal with respect toan exposed front surface of the LCD, the side surface at least partiallyexposed, the side surface further being configured to receive a userinput corresponding to a finger of the user contacting the side surface;a light source positioned to direct light into the opticallytransmissive element such that at least a portion of the light incidenton an internal surface of the at least one at least partially exposedside surface of the optically transmissive element undergoes totalinternal reflection (TIR) when the at least one at least partiallyexposed side surface is not in contact with the finger of the user; aset of light sensors positioned to receive light reflected by theinternal surface of the at least one at least partially exposed sidesurface and transmitted through at least one side surface of theoptically transmissive element after undergoing total internalreflection for at least one side surface of the optically transmissiveelement; and a memory device including instructions that, when executedby the processor, cause the computing device to: measure an intensity oflight reflected from multiple positions along the at least one sidesurface of the optically transmissive element; determine a baselineintensity profile for the computing device when the at least one sidesurface is not in contact with the finger of the user; monitor changesin the intensity of light detected by the set of light sensors; inresponse to a decrease in intensity of light reflected from one of themultiple positions with respect to the baseline intensity profile,determine the user input corresponding to the one of the multiplepositions; and process the user input using the processor.
 8. Thecomputing device of claim 7, further comprising: a display componentviewable through the exposed front surface of the optically transmissiveelement.
 9. A system for receiving a user input, comprising: aprocessor; a liquid crystal display (LCD) element including an opticallytransmissive element having at least one side surface beingsubstantially orthogonal with respect to an exposed front surface of theLCD, the side surface at least partially exposed, the side surfacefurther being configured to receive the user input corresponding to afinger of the user contacting the side surface; a light sourcepositioned to direct light into the optically transmissive element suchthat at least a portion of the light incident on an internal surface ofthe at least one at least partially exposed side surface of theoptically transmissive element undergoes total internal reflection (TIR)when the at least one at least partially exposed side surface is not incontact with the finger of the user; a set of light sensors positionedto receive light reflected by the internal surface of the at least oneat least partially exposed side surface and transmitted through at leastone side surface of the optically transmissive element after undergoingtotal internal reflection on the internal surface of the at least one atleast partially exposed side surface; and a memory device includinginstructions that, when executed by the processor, cause the system to:analyze the detected light to determine variations in a measuredintensity of the light, the processor further operable to determine areflection position corresponding to a decrease in the measuredintensity, the decrease in the measured intensity at the reflectionposition being indicative of the finger of the user contacting the atleast one at least partially exposed side surface at the reflectionposition when the decrease in the measured intensity with respect to adefault measured intensity at least meets a threshold value.